Some patients are candidates for stimulation therapy such as for sacral nerve stimulation or spinal cord stimulation therapy to treat issues such as incontinence, chronic pain, or related conditions. A stimulation device provides the stimulation therapy via an implantable medical lead that has a distal end at a stimulation site within the body. It is often necessary to utilize an implantable medical lead extension in order to span the distance from a proximal end of the implantable medical lead to the location of the stimulation device, which may be an internal or external location depending upon the desired configuration of the therapy.
For instance, it may be desirable to conduct a trial period of stimulation. This trial period allows an external stimulator to be used so that the patient is not required to undergo a full stimulation device implantation procedure and to lessen the risk of infection. If the trial is successful, then an implantable stimulator is fully implanted into the patient. When implanting the trial system, an implantable medical lead is implanted with a distal end being routed to the stimulation site. An implantable lead extension is typically then routed subcutaneously from the location of the proximal end of the implanted medical lead to an exit site nearby the location where the external device will be mounted to the patient where a connection to an external stimulation device is made.
When connecting the proximal end of an implantable lead to the distal connector of a lead extension, the proximal end of the lead is inserted into a bore within the distal connector, and then a set screw is tightened to lock the proximal end within the bore. The distal connector is compliant, and therefore tightening the set screw tends to bend the distal connector, potentially causing damage to the connector or the proximal end of the implanted lead and/or causing improper electrical connectivity. Anatomical movements after the implant may also subject the distal connector to bending forces, which may also potentially cause similar damage and/or improper electrical connectivity.